I read an article at an American History magazine talking about evangelical christian's antistatist roots and how it is rooted in the 1930s with their belief that FDR was a fulfillment of the prophecy of the antichrist and how many of the leading evangelists were strong critics of FDR and supported his opponents.

But looking at election returns from the 30s and 40s, many of the evangelical areas of the country heavily supported Roosevelt. It seems that the only areas with a large number of evangelicals that opposed him were mostly isolated: Northern OK, Southwest Missouri, East Tennessee, Southern Kentucky and random foothill counties in Virginia and North Carolina. Most of the other areas in the bible belt supported Roosevelt, and by landslide margins too.

I hadn't heard anything about evangelicals viewing FDR as the antichrist. Maybe some did, but I don't think it was widespread. Evangelicals did not typically vote as a bloc until fairly recently. You had issues such as Prohibition that cut across party lines, as abortion did before the 1980s. Tendencies to oppose a strong central government in the areas of the Upper South you mentioned may have a connection to evangelicalism in the type of local, independent church communities as opposed to more established high church traditions on the Coast or to the North. Evangelicalism took different forms in different regions, and at points has been strong in the Midwest and even in the Northeast - with political attitudes that different widely from one region to another.

I suspect it was regional, with northern evangelicals voting GOP and southern ones Dem, esp in 1952, 1956, 1976 and 1980. Other than 1928 and 1960, the rural poverty of most evangelicals would keep them Democratic until the late 1960s (and then again in 1976 one last time). As recently as 1980 one poll found Carter "clearly"leading Reagan among Evangelicals (which led Andy Rooney to quip "if you are born again do you get to vote twice?") Sadly the latest poll of "born again Christians" I am aware of is from 1984, when Time reported "born again Christians" voted for Reagan over Mondale 69-31. Today, of course, exit polls report "WHITE Evangelical or b.a.c." which greatly distorts the results in favor of the GOP).